Problems concerning polynomials / complex numbers

The equation gives us the total length of a cable between the points A and B

P=-5
Q= -2
O=0
R= 3

x is the centre of the cable.

The question is, where should the centre of the cable be to minimize toe total length of cable to all four points. And: what is the minimum (of the length of the cable)

Also, how can I graph this function that has absolute values in its equation?

Last part of this problem: A point S is added 7km away from O (so it adds to the equation + |x-7|. Where should it be for a minimal cable length?

Next question:
I need to find a fourth degree polynomial with the rational coefficients 2- i*squareroot 3 and squareroot2 +1 as two of the four zeros. How do I do this and what is the solution? Please help me.